Chapter 10 Animals with Armor

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Chapter 10 Animals with Armor

• When you have finished this
• Chapter, you should be able to
• List the basic characteristics of the
  crustaceans.
• Describe the structures and functions of lobsters
  and crabs.
• Identify important features of the smaller
  crustaceans and other marine arthropods.

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Lesson 26 Introduction to CrustaceansSection
10.1 The Lobster

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• Phylum Arthropoda
• Members of the phylum Arthropoda are commonly
  called the arthropods (meaning jointed
  appendages).
• Animals including the lobsters, crabs, shrimp,
  and barnacles have moveable arms and legs,
  referred to as jointed appendages.
• Arthropods also possess an external skeleton or
  exoskeleton composed of a tough fibrous material
  called chitin.
• The exoskeleton functions not only as a
  protective cover for arthropods but also as a
  place of attachment for their muscles.
• Classes of Arthropods
• Arthropods that have a separate head (cephalo),
  chest (thorax), and abdomen and have 5 pairs of
  legs are classified in class Crustacea.
• Arthropods that have 6 pairs of legs are found in
  the class Merostomata.

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Lesson 27 Introduction to CrustaceansSection
10.1 The Lobster

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• Class Crustacea
• Body Structure
• Crustaceans have three main body regions the head
  (cephalo), chest (thorax), and abdomen and have 5
  pairs of legs.
• Crustaceans are also called decapods (meaning 10
  legs).
• The first pairs of legs are the claws (chelipeds)
  used for seizing food and the other four pairs
  are the walking legs.
• The exoskeleton that covers the head and chest is
  the carapace.
• The head contains the eyes, antennae, and mouth
  parts used for feeding.
• The thorax contains the appendages used for food
  getting and walking legs.
• Crustacea also swim, using their paddle-like
  swimmerets located in the abdomen.

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Lesson 27 Introduction to CrustaceansSection
10.1 The Lobster

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• External Anatomy of the Lobster

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Lesson 27 Introduction to CrustaceansSection
10.1 The Lobster

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• Molting
• Crabs, lobsters, and shrimp shed their outer skin
  one or more times each year, a process called
  molting. Crustaceans can regenerate body parts.
• If an appendage is lost in a fight, another
  will grow back.

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Lesson 27 Introduction to CrustaceansSection
10.1 The Lobster

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• Life Functions of Crustaceans
• Crustaceans are largely scavengers.
• Food is digested in a one way digestive tract.
• The rapid beating of the mouth parts sends
  currents of water over the gills located under
  the carapace.
• Oxygen and other nutrients are transported around
  the body in the blood. The blood is blue, due to
  the presence of a copper based pigment,
  hemocyanin.
• Transport occurs in an open circulatory system.
• The nervous system has a ventral nerve cord and
  brain.

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Lesson 27 Introduction to CrustaceansSection
10.1 The Lobster

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• Life Activities of Lobsters
• Two common species of lobsters in our waters are
  the northern lobster and the spiny lobster.
  Lobsters are aggressive and often fight among
  themselves.
• Lobsters are predators, able to feed on other
  invertebrates such as mussels and sea urchins,
  which they grab with their claws. They also
  scavenge on the remains of dead animals.
• Food is digested in a one-way digestive tract
  consisting of a mouth, esophagus, stomach, and
  intestines. Wastes are eliminated through the
  anus.
• Lobsters use gills for breathing.
• Oxygen and nutrients are transported around the
  lobsters body in its blood. Blood is pumped by
  a one-chambered heart. Lobsters and all
  arthropods have an open circulatory system.
• The lobsters nervous system enables it to carry
  out a variety of responses. Its eyes are mounted
  on moveable stalks. Two pairs of antennae
  actively feel out the environment. A ventral
  nerve cord carries messages to and from the
  brain.
• Lobsters reproduce sexually. Fertilization is
  internal, and development is external.

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Lesson 27 Introduction to CrustaceansSection
10.1 The Lobster

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• Northern American Lobster and the Spiny Lobster

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Lesson 28 Describe the structures and
functions of the crab.Section 10.2 The Crab

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• Types of Crabs
• There are many species of crabs alive in the
  world today.
• The great diversity that exists is due to the
  fact that they have successfully adapted to many
  different habitats.
• Examples include, the mole crab, spider crab,
  fiddler crab, and the blue crab.

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Lesson 28 Describe the structures and
functions of the crab.Section 10.2 The Crab

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• Structures of the Crab
• The crabs body is divided into segments (the
  cephalothorax and the abdomen), which are covered
  by the carapace.
• Their head region has two eyes (on stalks) and
  antennae for perceiving touch and temperature
  stimuli. Their well-developed nervous system
  enables them to respond to stimuli and control
  muscular activities such as locomotion, via the
  ventral nerve cord.
• Like the lobster, crabs breathe by means of their
  gills and they transport oxygen and nutrients in
  an open circulatory system.

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Lesson 28 Describe the structures and functions
of the crab.Section 10.2 The Crab

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• Structures of the Crab
• The abdomen is small and flat and is folded
  between the crabs walking legs on its ventral
  side. You can tell the sex of the crab by the
  shape of its abdomen.
• The female has a U-shaped abdomen and the male
  has V-shaped abdomen.

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Lesson 28 Describe the structures and
functions of the crab.Section 10.2 The Crab

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• Reproduction in Crabs
• Crabs produce large numbers of offspring. The
  female carries a mass of eggs between her abdomen
  and thorax. Fertilization is internal and
  development is external. It is most adaptive for
  the crab to produce an abundance of fertilized
  eggs, since so many are eaten during their larval
  phase in the plankton population.

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Lesson 28 Describe the structures and
functions of the crab.Section 10.2 The Crab

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• Feeding in the Crab
• Crabs eat mainly dead plant and animal matter,
  although some graze on algae and others are
  predatory.
• They use their two sharp claws to tear and shred
  food.
• The food is passed to the mouth, where it is cut
  into small pieces by the mouthparts. Food is
  digested in a one-way digestive system.

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Lesson 29Aim How does the horseshoe crab
carry out its life functions?

• Characteristics of Horseshoe Crabs
• horseshoe crabs lack antennae and mouthparts.
• have six pair of appendages the first pair is a
  pair of pinching claws (the cheliceras), and the
  other five are the walking legs.
• covered by a domed carapace, which is followed by
  a long spiked tail (telson).
• classified in the class Merostomata.
• inhabits the waters along Americas Atlantic and
  Gulf coasts and along the Asian Pacific coast.
• has four eyes two simple eyes and two compound
  eyes located on the top of its carapace.
• behind the legs are book gills, which are used
  for breathing and locomotion.
• the horseshoe crab has copper-based hemocyanin in
  its blood for transporting oxygen

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Lesson 29Aim How does the horseshoe crab
carry out its life functions?

• Life Cycle of the Horseshoe Crab
• In late spring, when the tide is high, hordes of
  horseshoe crabs invade the sandy beaches and
  marshes.
• The females, carrying the smaller males clutched
  to their backs, congregate at the high-tide mark
  where they dig holes in the sand and lay hundreds
  on tiny pale green eggs.
• The males, still attached to the females,
  externally fertilize the eggs, which are then
  covered by sand.
• About two weeks later, the eggs hatch into ting
  swimming juvenile horseshoe crabs that are
  carried out to sea by the tide.
• As the horseshoe crab grows, its outer skin
  hardens to form a carapace. The horseshoe crab
  reaches maturity in about 8 years.
• During this period the horseshoe crab undergoes
  many molts, casting off its outer shell each time
  it grows.
• Horseshoe crabs can live as long as 20 years.
  Fossils of the horseshoe crab show that this
  animal has not changed very much throughout its
  more than 400 million year history. The
  horseshoe crab is often described as a living
  fossil.

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Lesson 29Aim How does the horseshoe crab
carry out its life functions?
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Lesson 30Aim Diversity Among Crustaceans

• CH 10 SECTION 10-3 DIVERSITY AMONG CRUSTACEANS
• Crustaceans range in size from nearly microscopic
  to absolutely huge. You are aware of the much
  larger ones , such as the lobster, crab, and
  shrimp, because they are popular seafoods.
• The shrimp looks somewhat like a small version
  of the lobster.

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Lesson 30Aim Diversity Among Crustaceans

• Floating and drifting on the ocean surface are
  the tiny copepods, which inhabit temperate waters
  and the larger krill, which are found in the
  Antarctic. Both form the basis of the marine
  food chains.
• COPEPODS KRILL

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Lesson 30Aim Diversity Among Crustaceans

• (4) Living under rocks and other debris in the
  intertidal zone from the Artic to the Chesapeake
  Bay is the scud. On sandy beaches from Canada to
  Florida living in the moist seaweeds in the
  strand line is the beach flea. Crustaceans, like
  the krill, scud, and beach flea, whose bodies are
  compressed laterally are called amphipods.

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Lesson 30Aim Diversity Among Crustaceans

• (5) Crustaceans, like the sea roach, whose bodies
  are flattened from top to bottom are called
  isopods. Isopods inhabit shallow coastal waters,
  some are parasitic.

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Lesson 30Aim Diversity Among Crustaceans

• (6) The barnacle lives attached to rocks and
  other hard surfaces (encrusting organisms). The
  barnacle feeds by filtering tiny plankton from
  the water using its feathery appendages called
  cirri. There are two types of barnacles the
  acorn barnacle and the gooseneck barnacle. The
  gooseneck barnacle are attached to long stalks
  which attach to a hard substrate.
• GOOSENECK BARNACLE ACORN BARNACLE